We converted all of our Fortis documents (over 700,000 documents) to DocuWare using DWControl files. That methodology was used from the start because I thought we would use Import Jobs. That turned out to be really slow in testing, so I ended up writing a .NET application that uploaded all the documents and generated indexes based on DWControl files.
If I had a CSV file, that would actually be even easier using the Platform SDK libraries in .NET. I only used DWControl files because I already had them all generated for the files to upload.
Is Platform SDK programming an option? That would be the most flexible way to go on this.